Carotenoids such as carotene, lycopene, bixin, zeaxanthin, cryptoxanthin, lutein, canthaxanthin, .beta.-apo-8'-carotenal, .beta.-apo-12'-carotenal and esters of hydroxy- or carboxy-containing members of this group have attained considerable importance as coloring agents. This importance has increased due to possible governmental regulations withdrawing or limiting the use of certain previously certified coloring agents.
Carotenoids are yellow to red pigments either identical with or related to pigments occurring in the plant and animal kingdom. Because of this relationship to naturally occurring pigments, carotenoids possess considerable interest as replacements for the synthetic coloring agents for use as coloring materials, e.g., for foodstuffs and pharmaceutical or cosmetic properties. In addition, the carotenoids are used in animal feedstuffs to provide, for example, enhanced egg yolk or skin pigmentation as well as a source of vitamin A activity.
Carotenoids are substances which are insoluble in water and which have relatively high melting points. Moreover, carotenoids are substances which are very sensitive to oxidation. These characteristics militate against direct employment of the crystalline materials for coloration of aqueous foodstuffs or feedstuffs or for use as a source of vitamin A since in this form, the materials are poorly absorbed or give poor coloring effects. The above-mentioned characteristics of carotenoids are especially disadvantageous in the coloring of aqueous media; since, as a result of the water-insolubility of carotenoids, it is quite difficult to obtain a homogeneous or sufficiently intense color effect. Hence, the water insolubility of the carotenoids prevents their direct use as coloring agents for coloring foodstuffs having an aqueous base such as fruit juices, mineral water with fruit juices or with fruit juice flavors, ice-cream, etc. and dry products which are to be added to water in their original form or first prepared with water prior to use such as, for example, pudding powders, soup powders, powdered eggs, tomato concentrates and dry beverage bases such as lemonade powder.